The present invention relates in general to carpet stretchers, and more particularly to a manually powered carpet stretcher with a locking mechanism.
In the patent to Payson, U.S. Pat. No. 3,692,278, issued on Sept. 19, 1972, for Carpet Stretcher With Ratchet Handle, there is disclosed a hand powered carpet stretcher with telescopic tubular members. A pivotal handle extends from a pin head. A link interconnects the handle and a tubular member. A ratchet interconnects the handle and the link. A pawl is mounted on the handle to engage the link to lock the pin head at a selected position. A rod or the handle is actuated to release the pawl from the ratchet.
The patent to Payson, U.S. Pat. No. 3,693,936, issued on Sept. 26, 1972, for Carpet Stretcher Improvements, discloses a sliding tube extending rearwardly from a pin head into a tubular extension member. A handle is pivotally attached to the rear of the pin head. A link interconnects the handle and the tubular extension member. A rack is formed on the sliding tube and a pawl is mounted on the tubular extension member. The pawl engages the rack to retain the sliding tube in an adjusted position relative to the tubular extension member. A rod retracts the pawl from the rack to release the sliding tube. In another version of the carpet stretcher, a ratchet is on the link and the pawl is mounted on the handle. A lever on the handle retracts the pawl from the ratchet to release the pawl from locking engagement with the rack. In still another version of the carpet stretcher, the locking tube is formed with a rack. The pawl is mounted in a pawl housing, which is mounted on the tubular extension member. The link is also secured to the pawl housing. A second link extends from the first-mentioned link to a lever for the pawl. When the handle is moved downwardly to stretch the carpet, the lever releases the pawl to enable a spring to urge the pawl in engagement with the ratchet. When the handle is raised, tension on the carpet is relaxed and the lever retracts the pawl from engagement with the rack.
In the patent to Payson, U.S. Pat. No. 3,791,624, issued on Feb. 12, 1974, for Extendible Tube Assembly, there is disclosed a carpet stretcher in which tubular members are disposed in a telescopic arrangement. A lock tube is fixed in one tubular member and extends into another tubular member. A lock collar that may be spring loaded or may be tiltable through engaging and non-engaging angles engages the lock tube to retain the tubular members in an adjusted fixed position relative to one another. The lock collar is released by the actuation of a longitudinally extending rod within a tubular member or a concentric tube disposed within a tubular member. This patent also discloses a pin head from which extends a locking shaft that slides into a tubular member. A link interconnects a handle and the tubular member. A rack and pawl arrangement between the tubular member and the lock shaft holds the lock shaft in a selected position relative to the tubular member. A cable and lever or a push rod on the handle retracts the pawl from the rack to release the lock shaft.
The patent to Payson, U.S. Pat. No. 3,917,225, issued on Nov. 4, 1975, for Carpet Stretcher Improvements discloses a handle pivotally attached to the pin head. Extending from the pin head is a sliding rod that is received by a tubular member. A link interconnects the handle with the tubular member. A spring loaded lock collar on the tubular member has an aperture to receive the sliding rod and is movable between a locking position and release position for locking engagement and disengagement with the sliding rod. A spring urges the lock collar into lock engagement with the sliding rod and a lever and cable arrangement extending from the handle releases the lock collar from locking engagement with the sliding rod. In a modified carpet stretcher, there are two lock collars to perform a stepping action. The rear collar is movable forwardly of the locking rod, while the forward collar locks the locking rod against movement as the handle is raised and is locked in position as the handle is lowered. The coupling assembly can be pumped rearwardly by the handle. Lifting of the handle disengages the locking action of the rear collar and releases the applied tension to the carpet. Full release is attained by disengaging both collars to free the sliding rod within the tubular member.
In the patent to Payson, U.S. Pat. No. 4,076,213, issued on Feb. 28, 1978, for Locking Tube Assembly, there is disclosed extensible, telescoping tubular members. One member includes a spring loaded, pivotal lock collar that is apertured to receive a sliding rod. The sliding rod is attached to the other tubular member. A lever is attached to the collar and extends radially outward from the one tubular member. The lever is actuated to release the lock collar from locking engagement with the slding rod.
Roberts Consolidated Industries, City of Industry, California, has manufactured and sold power stretchers. In one model, a switch on the handle is employed to lock a stretch in any position.